In response to this challenge, the Department for Education (DfE) asked its partners: what will the next generation of schools look like? This question gave rise to ‘GenZero’ – a research project led by Mott MacDonald to develop prototypes for net-zero schools that can be produced through offsite construction. We were appointed as the integrator, project managing a team of 13 partner organisations. GenZero builds on our track record creating standardised designs for the Priority School Buildings Programme, which delivered 90 primary schools using offsite solutions in just five years. However, GenZero goes further, developing a platform design for manufacture and assembly (P-DfMA) solutions that are aligned with net-zero emissions, more flexible and cost-effective, and which provide better spaces and greener places for working, learning and thriving, for students and staff.
What the users said
Our approach to GenZero was informed by our analysis of post-occupancy evaluations from 54 recently completed or refurbished schools. We surveyed the schools based on site visits and questionnaires with local staff, who provided feedback on the buildings’ quality, functionality and effectiveness. These findings were then presented to the DfE. That data informed the design of the many different spaces required to create the new exemplar school: classrooms, laboratories and workshops, corridors and stairways, lavatories and utility rooms, offices, staff facilities and medical rooms, theatres, sports halls and changing facilities, kitchens and canteens – and outdoor spaces too.
We looked at the needs of different schools – from primary up to sixth form, and from small, single-form entry up to large multi-form. We also looked at schools for those with special educational needs (SEN).
Design for comfort and wellbeing
GenZero schools had to be resilient to the physical impacts of climate change, anticipating 2°C to 4°C warming above the pre-industrial global average temperature. Cooling is achieved using passive cross ventilation. Outside air will be drawn into classrooms and up through the building by convection, known as the stack effect, exiting via ventilation shafts in the roof. Wherever possible, plants and trees will be incorporated into landscaping, which will help cool the supply air. Supplementary air movement will be provided by ceiling fans.
It is now well-established that individuals’ wellbeing and health benefit from contact with the outdoors. Learning outcomes do too. So GenZero schools have large windows, letting in light and offering generous views. And where space allows, they incorporate natural landscaping, with trees providing shade and cooling during summer. Both urban and rural plans include covered external areas for outdoor learning.
A modular approach
We developed a platform solution that would enable every school to be built using a kit of standardised components, with the requirements of each school met by combining those components differently. Platforms are common in other industries but rare in construction: automotive manufacturers use many of the same components to build a variety of vehicles. That approach has been adopted here. While the DfE defines the spaces a school requires, our platform – a standardised kit of parts – gives flexibility to create bespoke solutions.
The GenZero platform has been designed digitally. All of the modules and their component parts are virtual ‘objects’ that can be selected and placed within a school design. The design ultimately generates the schedule of modules and components for manufacture and delivery to site.
Components are designed to achieve outstanding noise and thermal insulation; using P-DfMA will deliver very high build quality. Wood was selected as the primary construction material, meeting structural and aesthetic requirements, all building regulations on fire safety, as well as supporting climate goals through substitution of carbon intensive materials such as concrete, steel and bricks and acting as a carbon store.
Flexibility to meet present and future needs
Kit of parts construction coupled with a platform approach creates the possibility of reconfiguring spaces, dividing, adding or subtracting components as needed, to adapt to future needs, including curriculum changes.
To support each school’s sense of community and collective wellbeing, and provide the focus for pastoral support, the common areas – canteen and halls – form the core. Other functions such as bathrooms, heating and mechanical, electrical and plumbing (MEP) units are distributed across all three buildings.
Schools are created by combining modules designed to support different functions: a teaching module, containing classrooms and offices; a commons module containing mid-sized communal spaces such as the library, dining room and changing rooms; and a module housing large volume spaces such as lecture theatres, assembly halls and sports facilities.
Using these modules, we designed three basic school profiles, each with variations for large and constrained sites:
- Core curriculum – with a focus on more classrooms to teach the academic subjects
- STEM/vocational – with larger spaces for technology, catering or lab work
- Cross-curriculum – a balance between core curriculum and STEM/vocational spaces
These school profiles are all based on a standardised grid layout, developed in partnership with the DfE. Internal spaces are aligned to a 3.6m by 7.8m grid. While the depth of rooms remains constant at 7.8m, the length of the room can be scaled up or down in 3.6m increments, with a sub-grid of 1.8m allowing for greater flexibility. This leads to a range of classroom sizes: 55m2 (standard classroom); 69m2 (enhanced classroom); 83m2 (art room or science lab); 97m2 (practical space) or 111m2 (workshop).
These main spaces run along both sides of a central corridor which is 2.4m wide, while ancillary space alongside the classrooms is 1.4m wide to accommodate small offices and voids for crossflow ventilation.
The same concept was applied to the ‘commons’ building combining two rows of teaching and ancillary accommodation either side of a generous dining space, part double height and part mezzanine, where spaces such as the learning resources centre (LRC) might be situated.
Sports hall, main hall and activity studio are accommodated in an 18m span volume.
All spaces can be subdivided with partition walls.
These modules allow six standard sizes of secondary schools to be built. Each size can be configured differently – with modules arranged as separate single storey buildings in rural locations, or integrated to create a compact five-storey block for inner cities. Overall, it means our standard kit of parts can create 72 different standard school types, which many more variations possible.
Up to 85% of each building will be made from prefabricated panels, but with toilets, staircases and plant rooms delivered as complete volumetric modular units, simply lifted into place and connected. MEP elements such as heat pumps are also brought to site as complete ‘plug-and-play’ components.
P-DfMA allowed each component to be value engineered. Timber external facades and partition walls are lighter than conventional construction materials, enabling materials savings on foundations. Day-to-day energy efficiency is aided by the high thermal efficiency of the building envelope, heat pumps which recover and re-use heat, natural ventilation which minimises need for air conditioning, and solar panels to produce onsite energy.
Net negative
The final design will deliver net-negative carbon emissions. Because trees absorb carbon CO2 from the atmosphere as they grow, building the superstructure from wood will make this part of each school carbon negative: concrete floors, MEP and other building products will generate embodied carbon of 1200tCO2e for the typical GenZero school, but this will be offset by the 1700tCO2e embodied in the timber. Estimated energy intensity is a highly efficient 40kW/yr/m2, mostly due to high efficiency building services, catering, lifts, external lighting and energy efficient small power. This is mitigated by onsite energy generation of 53kWh/yr/m2 through the use of PV cells.
Trailblazing P-DfMA
GenZero is aligned with the UK’s pathway to net-zero and a flagship for the Royal Institute of British Architects 2030 Climate Challenge, which means new designs adhere to science-based targets for greenhouse gas reductions. It also meets London Energy Transformation Initiative (LETI) targets on carbon efficiency.
GenZero is also a trailblazer for the UK’s government’s drive for platform approaches across its estate – hospitals, law courts, police stations, prisons, barracks, and other government owned buildings. New schools can be easily and quickly developed by virtually assembling components to meet school requirements, leading to offsite manufacture and ‘flat-pack’ assembly on site, resulting in significant reductions in time and construction-related disruption, and improvements in worker safety. Prefabricated construction also helps to drive down waste compared to traditional construction techniques – one of the reasons that P-DfMA is cost effective compared to non-standardised delivery.
The focus on light, bright, well-ventilated interiors, communal spaces and outdoor areas will have mental and physical health benefits. GenZero schools will be great places to learn.
We are the lead technical advisor for the first school – St Mary’s primary school and nursery in Derby. The planning application was submitted to the local council in June 2022.